Chapter 8 and Chapter 9 Flashcards
se = σ / sqrt(n)
Equation for the standard error (standard deviation) of a distribution of sample means.
Name the 2 assumptions that must be met for a distribution of sample proportions to be normally distributed.
n*p >= 5
n*(1-p) >= 5
se = sqrt( [p*(1-p)] / n)
Equation for the standard error (standard deviation) of a distribution of sample proportions.
The empirical rule states that _____ % of values of a normal random variable are within +/- 1 standard deviation of its mean.
68%
The empirical rule states that _____ % of values of a normal random variable are within +/- 2 standard deviation of its mean.
95%
The empirical rule states that _____ % of values of a normal random variable are within +/- 3 standard deviation of its mean.
99.7%
The confidence associated with an interval estimate.
Confidence Level
The confidence level expressed as a decimal value.
Confidence Coefficient
An estimate of a population parameter that provides an interval believed to contain the value of the parameter.
Interval Estimate
1 - α
Confidence Coefficient
When σ is known, multiply the ____ and _____ to calculate the margin of error for an interval estimate for the population mean.
Z-Value at α/2
Standard Error of the Sample Mean Distribution
When σ is unknown, multiply the ____ and _____ to calculate the margin of error for an interval estimate for the population mean.
T-Value at α/2
s / sqrt(n)
σ
Population Standard Deviation
s
Sample Standard Deviation
x bar +/- margin of error
Interval Estimate for a Population Mean
A family of probability distributions that can be used to develop an interval estimate of a population mean whenever the population standard deviation σ in unknown and is estimated by the sample standard deviation s.
T Distribution
p bar +/- margin of error
Interval Estimate for a Population Proportion
A parameter of the t distribution. When the t distribution is used in the computation of an interval estimate of a population mean, the appropriate t distribution has n-1, where n is the size of the sample.
Degrees of Freedom
A tentative assumption about a population parameter.
Null Hypothesis
The opposite of what is stated in the null hypothesis.
Alternative Hypothesis
Used to determine whether a statement about the value of a population parameter should or should not be rejected.
Hypothesis Testing
Hypothesis of no change.
Null Hypothesis
The equality portion of the hypotheses always appears in the ____ hypothesis.
Null Hypothesis
Name the 3 forms of hypothesis tests.
One-Tailed (Lower Tail / Decreasing)
One-Tailed (Upper Tail / Increasing)
Two-Tailed
As degrees of freedom increases, the difference between the t distribution and the
standard normal probability distribution _____ .
Decreases
At 95% confidence, α equals ____ .
0.05
True or False
The t distribution is used when computing interval estimates when σ is known.
False
True or False
When σ is unknown, the sample standard deviation s is used to approximate the population standard deviation σ when computing interval estimates.
True
H(o) : μ >= μ(o)
H(a) : μ < μ(o)
One-Tailed (Lower Tail) Hypothesis Test
H(o) : μ <= μ(o)
H(a) : μ > μ(o)
One-Tailed (Upper Tail) Hypothesis Test
H(o) : μ = μ(o)
H(a) : μ =/ μ(o)
Two-Tailed Hypothesis Test
True or False
When p is unknown, the sample proportion p bar is used to approximate the population proportion p when computing interval estimates.
True
Multiply the ____ and _____ to calculate the margin of error for an interval estimate for the population proportion.
Z-Value at α/2
Sqrt( [p bar * (1-p bar) ] / n)
In a(n) lower / upper tail one-tailed hypothesis test, the alternative hypothesis suggests that the actual population mean μ is less than the hypothesized population mean μ(o).
Lower
In a(n) lower / upper tail one-tailed hypothesis test, the alternative hypothesis suggests that the actual population mean μ is greater than the hypothesized population mean μ(o).
Upper
The type of error that occurs when the null hypothesis is rejected when it is actually true.
Type I Error
The type of error that occurs when the null hypothesis is not rejected when it is false.
Type II Error
Another name for interval estimate.
Confidence Interval
The +/- value added to and subtracted from a point estimate in order to develop an interval estimate of a population parameter.
Margin of Error
A value that is compared with the test statistic to determine whether the null hypothesis should be rejected.
Critical Value
The probability of making a Type I error when the null hypothesis is true as an equality.
Level of Significance
A probability that provides a measure of the evidence against the null hypothesis given by the sample.
P-Value
The probability of correctly rejecting the null hypothesis when it is false.
Power
A graph of the probability of rejecting the null hypothesis for all possible values of the population parameter not satisfying the null hypothesis.
Power Curve
A statistic whose value helps determine whether a null hypothesis should be rejected.
Test Statistic
The Excel function that returns the normal distribution for the specified mean and standard deviation.
NORM.DIST
The Excel function that returns the inverse of the normal cumulative distribution for the specified mean and standard deviation.
NORM.INV
Name the Excel function used to create a confidence interval for a population mean when σ is known.
CONFIDENCE.NORM
Name the Excel function used to create a confidence interval for a population mean when σ is unknown.
CONFIDENCE.T
Name the Excel function used to compute the p-value for a one-tailed hypothesis test about a population mean when σ is unknown.
T.DIST.RT
Name the Excel function used to compute the p-value for a two-tailed hypothesis test about a population mean when σ is unknown.
T.DIST.2T
Name the Excel function used to compute the p-value for a one-tailed hypothesis test about a population mean when σ is known.
Z.TEST
Name the Excel function used to create a confidence interval for a population proportion.
CONFIDENCE.NORM
Name the test statistic used for a hypothesis test about a population mean when σ is known.
Z
Name the test statistic used for a hypothesis test about a population mean when σ is unknown.
T
Name the test statistic used for a hypothesis test about a population proportion.
Z
Name the Excel function used to compute the p-value for a one-tailed (lower tail) hypothesis test about a population proportion.
NORM.S.DIST
Name the Excel function used to compute the p-value for a one-tailed (upper tail) hypothesis test about a population proportion.
1 - NORM.S.DIST
Name the Excel function used to compute the p-value for a two-tailed hypothesis test about a population proportion.
2 * NORM.S.DIST
